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Simple Interest Calculator
Simple interest is charged only on the original amount, never on interest already earned, which makes it different from compound interest. Enter the principal, the annual rate and the time period and this calculator shows the interest, the total amount, and the equivalent monthly figure.
Use the tool
How to use the Simple Interest Calculator
- Enter the principal amount, annual interest rate and time in years.
- Adjust any optional settings to match your page, business or campaign.
- Click the button to generate your result instantly — nothing is uploaded; the tool runs in your browser.
- Copy the result, or download it as a file where that option appears, and paste it into your site, document or campaign.
Frequently asked questions
How is simple interest worked out?
Principal multiplied by the annual rate multiplied by the time in years. On 10,000 at 5 percent for 3 years, that is 1,500 in interest.
How does it differ from compound interest?
Compound interest also earns interest on past interest, so it grows faster over time. Simple interest grows by the same amount every year.
What if the period is in months?
Enter it as a fraction of a year: 6 months is 0.5 years, 18 months is 1.5 years.